Keith Woodford explains how our forestry policy is not fit for purpose and will lead to perverse outcomes without much better targeting of permanent forests on the back-country

Keith Woodford explains how our forestry policy is not fit for purpose and will lead to perverse outcomes without much better targeting of permanent forests on the back-country

In recent months I have been writing about land-use transformation that will be driven increasingly by carbon trading. If New Zealand is to approach net-zero carbon, then it can only be achieved by a combination of modified lifestyles plus new technologies that either don’t yet exist or are yet to be commercialised. Even with all of these things, it will still require lots of forest plantings to offset carbon emissions from elsewhere in the economy.

A key point underlying the recent articles I have written is that the implications for rural-landscape change have been under-estimated and poorly communicated. A key thrust of this current article is that it is only by permanent forests rather than multiple-rotations of production forests that the march of the pine trees across the landscape can be managed.

To put some broad numbers around the situation, New Zealand’s current annual emissions of greenhouse gases, as officially measured, are approximately 80 million tonnes of carbon dioxide equivalent (CO2e). One key challenge in controlling these total emissions is that New Zealand’s population has been increasing recently at between 1.5 percent and 2 percent per annum, driven largely by immigration.  These population growth rates are remarkably high for a developed country.

New Zealand’s forestry offsets as officially measured are currently around 24 million tonnes per annum of CO2e.  This comes from the 1.73 million hectares of production forest. Nearly all of these forests will be harvested over the next 30 years.

Once existing forests have been harvested, that land can never provide more credits. Indeed, these lands must be replanted in forest just to avoid carbon levies being charged.  This is because the essence of carbon trading is that only new carbon storage is rewarded. Once forests are harvested, then new carbon sequestration from replanted forests is needed to balance out what was lost from harvesting.

This means that if all New Zealand does is replace harvested forests, with no new forests from farmland, then it will be reporting back to the UNFCCC that its carbon sequestration is rapidly declining towards zero, whereas sequestration needs to increase. 

To say that a little differently, replanting the current forests will not stop New Zealand going into reverse-gear sequestration rates. New Zealand needs to both replant harvested forests and also plant lots of new forests on farmland if it is to maintain current levels of offsets. And then plantings need to increase still further if offsets are to increase as the Government intends.

To put some numbers around that, if New Zealand wants to just maintain the current annual offset rate of around 24 million tonnes of CO2e, and if it plans to do this with production forests, then as well as replanting existing forests, it will need to plant new pine forests, with these new plantings marching across current farmland at about 65,000 hectares each year. All of these new plantings have to come from farmland.

The reason the march across the landscape has to be so fast is because production forestry is a weak provider of carbon sequestration. Averaged out over multiple rotations, these production forests only store around 350 tonnes of carbon dioxide equivalent.  Under the proposed averaging system, credits from all of this are earned over the first 17 years.

This creates a perverse situation of short-term investor behaviours to generate cash being driven by the long-term benefits, yet the long-term benefits are only modest because of the harvesting.

As one scenario, if New Zealand wants to work towards sequestering around 35 million tonnes per annum of CO2e by 2050, and with interim targets along the way, then that is an additional 10 million tonnes sequestration per annum from currently. To achieve that with radiata-pine production forests, then the march across the landscape with new plantings is no longer 65,000 hectares, but around 100,000 hectares per annum, at least until 2050, and in all likelihood continuing on from there.

To put that in perspective, the total area of sheep and beef farming area is around 8.8 million hectares. So, by the end of this century the pastoral countryside, apart from the dairy land which is still too expensive to go into trees, and some dry land in Central Otago, would be a solid mass of pine trees. The current $10.5 billion of meat and co-product exports would be gone.

The obvious alternative is to focus on the steep erodible land and plant permanent forests. For example, each hectare of permanent pine forest will sequester between 1000 and 1350 tonnes of CO2e over a fifty-year period. Carbon sequestration will also continue beyond 50 years, but the official ‘look-up’ tables stop at that point, so the tables need to be extended.

The reason for focusing on radiata pine for the permanent forests is that these are the trees that grow the fastest in New Zealand conditions. Native trees sequester CO2e at around one quarter of the rate of pine according to the official ‘look-up’ tables.

However, in the long term it is feasible for mature radiata pine be replaced by indigenous forests. This requires an initial seed source for natives to grow in the shady spaces as mature pine trees die and fall. In big forests beyond the reach of seed-spreading birds, nature will need some help from humans to get the process started. That will be the task for future generations, perhaps 100 years from now.

With permanent pine forests, it would take about 1.3 million hectares planted progressively over the next 30 years to be giving us around 35 million tonnes of CO2e offsets at that time, with those offsets continuing for many years thereafter.  Co-incidentally, that area of around 1.3 million hectares aligns with estimates of low-productivity erodible sheep and beef land that would benefit from being forested.

Permanent forests set up with radiata pines are not the perfect solution. However, they are the only solution with potential to provide the carbon offsets that will be needed if New Zealand is to meet its Paris commitments without destroying pastoral farming.

The big risks with pine forests are fires and exotic pests. So far, New Zealand has been blessed that the pests of radiata pine have not reached New Zealand’s shores. An attack of pine beetle could destroy a production forest, but in the case of mature permanent forests this might also facilitate conversion to indigenous forests.

The risks of fire relate both to production and permanent forests, but with permanent forests the area of pines can be much less.

The problem right now is that Government policies are encouraging behaviours for setting up of production forests on the better classes of land. The balance is out of kilter with long-term needs to get the right trees in the right place.

The key emergent question is how can New Zealand put in place the incentives and institutional frameworks to plant around 45,000 hectares of permanent forests per annum on the steep erodible lands, such that conservation benefits and carbon sequestration go hand in hand.

 I have some ideas as to how that could be done, but that is a big discussion for another day. What is clear is that current policies are not going to get the right trees in the right place.

*Keith Woodford is a retired academic who now holds an honorary position of Professor of AgriFood Systems at Lincoln University, NZ. He now consults through his own company AgriFood Systems Ltd. Articles written since 2010 are archived at He can be contacted at

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> New Zealand’s current annual emissions of greenhouse gases, as officially measured, are approximately 80,000 tonnes of carbon dioxide equivalent (CO2e)

Is this off by a factor of 1000? Google tells me we emit 81 million tonnes of CO2 equivalent.

Less nit-picky, the focus (and incentives) around sequestration on the land are short-sighted. If you harvest wood and use it to build new houses, those houses sequester the carbon just as effectively as the trees would have. And then re-planting (and re-harvesting, and re-planting) then becomes an ongoing carbon sink year after year to net against our annual carbon "deficit", not a one-time band-aid to net against a cumulative carbon "debt".

Yes you are correct, in five places I said thousand when I meant million. Mea culpa. Now fixed up.
In regard to using the timber for building houses, yes once again you are correct for timber used that way. BUT, only a very small proportion of our timber is used in that way. Much of it in China is used for concrete formwork and then burnt (hopefully for fuel rather than totally wasted). We need better data on how all of our logs are used.

Thanks for the reply, Keith. The argument that much (or most?) of our produced wood is burned makes a lot of sense. I guess we could try to track how the wood is used to determine credits for growers, but it might be simpler to
- assume that all carbon is returned to the atmosphere (as in the current scheme), but
- give carbon credits to homebuilders and other users where the carbon is not released.

In the "incentivise growers" case there are weird outcomes -- growers would be willing to sell to homebuilders for less than to other users -- whereas in the "incentivise users" case things would be simpler: homebuilders would be willing to pay more for wood, and homebuilding would naturally be encouraged.

Still, passing those incentives on to overseas users would be difficult.

Cutting down and transporting all those logs comes at a Carbon cost though. Lots of empty trucks driving into the forests then lugging them out one by one. Then processing etc. Still, we could just plant more trees to offset all that activity.

STEEL, I will do some digging to try and find out what really does happens to our logged timber but I am not sure I will get quick answers. I am going to hazard a guess that is it only around 10 percent that it used for durable products. This is part of the reason that pruning and thinning has largely gone by the wayside.

That work had been done. It will likely form the basis of the harvested wood products in the carbon averaging. The important thing to realise is that structural timber, MDF, and particle board have relatively long half lives, about 20 years or so. It all depends upon what the customer does with the log.

I this just taxation by shady foreign entities in disguise?

Taxation or not, I fully support it. I wish this 'taxation' started 50 years ago... I'm 33 and I really hope the natural world won't look very different 50 years from now.


Back then we were all scared of the next ice age that was clearly beginning and scientifically documented, well, that, and nuclear bombs dropping out of the sky without warning and oil running out in the next 3 years:

There is always something that you're supposed to be scared of, or angry about.

So just because *some* scientists back then got *some* things wrong, let's never trust scientists again. Gotcha.


No. Just to be aware that it is very easy to fall for a compelling story that stirs deep emotion. Con men are extremely convincing, that is their expertise.

Nuclear bombs falling out of the sky was real:


Paul Ehrlich ... Greenpeace ... Al Gore .. it's an inconvenient truth that the environmental movement has been beset by con artists for generations ...

.. all of them lacking proper science behind their hysterical ravings ..

And Galileo was burnt at the stake. Your point being? How do you decide which "compelling story" to fall for?


That is my point. I believed the fashionable ideas of the day, some were valid, some not. It is easier to be wrong than right. So I get edgy when I find other people all seem to believe the same thing. I start wondering if I am being a lemming, or someone else's useful idiot. Are their unidentified assumptions? Does a particular interested party or parties benefit from this, unknown to me? Are there malevolent actors I am unaware of? Hence the question about taxation in disguise.

That logic can be applied to anything, really. I guess it's a personal choice. You choose the group of people you believe. I prefer to believe the overwhelmingly large number of climate scientists over some random facebook moms.


That is my problem too. The only chap I know who has spent his live studying glacial cores from Antartica looking at climate change swears there is no evidence it is manmade. The chap who has the best forecasting record that I know of, Martin Armstrong, thinks it is cyclical. It could easily be a cyclical phenonemon that reverses quite naturally.

Science is best when it is in turmoil, not when everyone thinks alike. A scientist should always be sceptical of his theories, looking to disprove them, improve them, identify their weaknesses, searching for unexplained effects, looking for limits on their applicability. The attempt to disgrace "sceptical scientists" is disgusting to me and makes me question the entire narrative. I therefore now sit firmly on the fence, enjoying the spectacle.

Not quite sure where the Facebook moms came from. I was always led to believe that mother knows best.

Roger, There seems little doubt that the temperature turning points precede the CO2 turning points. That is very clear from the ice cores, with the lags of the order of 600 years. Those outcomes are consistent with temperature driving CO2 and not the other way round, at least within historical timescales. The fundamental physical theory behind this as to why CO2 levels increase when temperatures increase is also very clear relating mainly to oceanic outgassing, and the lags that link to deep water ocean currents. Similarly, the fundamentals of greenhouse gases as orginally discovered by Arrhenius are also very clear. But the ice core data tells us that at least without man interfering, it is the sun that is the dominant driver. But how this all plays out when man does interfere, and in a dynamic and complex environment, must surely not be settled science. At this point, that is as far as I am prepared to go, by arguing that all theories must be open to scrutiny, including the challenges of quantification. Unfortunately, in the current social environment, if your ice-core mate were to debate some of these things in public then it coud be career limiting.

The science underlying the regulation of earth's climate by greenhouse gases has been well understood since the 1890's. Nobody debates evolution or relativity any more. Move on people.

Yeah, really well understood. "For over thirty years,climate scientists have presented a likely range for ECS that has hardly changed. The ECS range 1.5−4.5K in 1979 (Charney1979) is unchangedin the 2013 Fifth Assessment Scientific Report (AR5) from the IPCC. AR5 did not provide a best estimate value for ECS, stating (Summary for Policymakers D.2):"No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence".


CourtJester your response is exactly like Galileo's accusers. A true scientist would continue to evaluate facts rather say "the science is settled".
There are massive amount of scientists that do not believe in MAN MADE climate change.
Most people accept the climate changes and has always been driven by the sun.

CourtJester your response is exactly like Galileo's accusers. A true scientist would continue to evaluate facts rather say "the science is settled"

OK, but the general consensus among climate scientists is that anthropogenic climate change is possible to the point where some believe it exists beyond a doubt. Those same scientists do not seem to be claiming 'science is settled'. On the contrary.

I used to believe the 99% of scientists who said eating fat, caused heart disease, which is why I became a vegan but now we know they were wrong so I now believe the 99% of scientists who say we have 12 years to live in a climate emergency crisis, which is why I am still a vegan.

Galileo wasn't burnt at the stake. Ignorance will surely cost us all dearly though.

You're right, it was Giordano Bruno who was burned at the stake

On Ash Wednesday, 17 February 1600, in the Campo de' Fiori (a central Roman market square), with his "tongue imprisoned because of his wicked words", he was hung upside down naked before finally being burned at the stake.[35][36] His ashes were thrown into the Tiber river. All of Bruno's works were placed on the Index Librorum Prohibitorum in 1603. The inquisition cardinals who judged Giordano Bruno were Cardinal Bellarmino (Bellarmine), Cardinal Madruzzo (Madruzzi), Cardinal Camillo Borghese (later Pope Paul V), Domenico Cardinal Pinelli, Pompeio Cardinal Arrigoni, Cardinal Sfondrati, Pedro Cardinal De Deza Manuel and Cardinal Santorio (Archbishop of Santa Severina, Cardinal-Bishop of Palestrina),_trial_and_exe...

Bugger, Galileo died from fever. Must have been one of those highly charged cosmic particles from deep space entering our atmosphere ever more frequently due to our weakening electromagnetic field, that nudged one of your neurons after affecting the upper atmosphere, thus driving the extreme's of Earth's weather and the long term planetary climate cycle. But yea. could have been too much CO2 in your brain too. The science is not settled.

I wouldn't say it is a case of not trusting them. Rather a case of not taking what they say as gospel.

Science is a lot of theories, based on a lot of assumptions, with a lot of the results being open for interpretation.

"One key challenge in controlling these total emissions is that New Zealand’s population has been increasing recently at between 1.5 percent and 2 percent per annum, driven largely by immigration. These population growth rates are remarkably high for a developed country." These two sentences encapsulate a core issue here that no one appears to want to enter into a discussion on. I have asked this before, and do so again; in a finite world what population base can this country sustain?

A Keith points out, to absorb our COe2 emissions we essentially end up killing our food production land, if we are to use trees as the means to counter the COe2. So the debate needs to consider all the implications.

If only we had an environmental party that would campaign on a policy of zpg.

I would restate this as "if only we had a party that had a primary focus on the environment". A primary aspect of this focus would be developing policies emphasizing sustainability rather than growth. The current "green" party is supporting clearly unsustainable policies that are clearly detrimental for the future environment. Sustainable is on the opposite end of the spectrum from having six tamariki.

Immigration growth fuels GDP growth. GDP growth is the 'untouchable' metric that wins or loses elections... I wish this wasn't the case.


GDP per capita growth is what you want. That can be achieved without population growth (e.g. improved technology, investment, training). If GDP per capita is decreasing while the population is increasing the country's living standard is likely falling.

Yea, but that is hard
Governments want easy
Screw GDP, I want my culture and people

This is why on the last thread on this topic I asked what will our population be in 2050. A mate of mine once said money isn't an issue. Either earn more or spend less. In this case we seem set on carry on as we are, just plant more trees to balance out our behaviour. There are so many initiatives that could be taken to help reduce our carbon footprint if this is really required but I see barely any carrots and sticks being waved around.The latest one, investigate the price of petrol and try and modify the market to bring DOWN the price of petrol. Other than fishing for votes, what sort of signal is that? Lets just plant some trees.

I propose a population of two million Murray

Not really if we need the wood to build houses in 30 years and it replanted at staggered times whats the difference ? Unfortunately native forest, while it looks great is VERY slow to grow, costs a fortune in small trees, cannot be grazed while it grows and then cannot be cut down when it gets over 5 meters so hence has zero incentive to plant it....currently. If the government wants to create an "Offset" like it currently does with "Wetlands" which is a major rippoff really and switch it to native forest, then sure, great idea for future generations in hundreds of years time to appreciate.

Leave the carbon zero policy and long term negative effects to Labour, Greens and Winston first and the money making out of the policy to others. There is always money to be made out policies like this. I only wish I had the sense and capital to climb on the bandwagon

. . Yes . . Ultimately it wont alter the climate one bit ... but alotta smart folks will get rich off it ... and our supply of valuable food production land will diminish...

I'm putting this policy up there with Kiwibuild as Labours biggest plonker of the term award ... still a year to go , but ...

Sure, let's not do anything to reduce emissions because it won't matter, right? I don't want to see what happens when every other country thinks the same way.

No ... other countries think quite differently ... those who think for themselves, rather than swallow hook line & sinker all the rubbish the U.N. orders them to believe ...

It's all rubbish in your opinion? Based on what?

Here is an example of another country thinking differently to Cindy and Simon's wasteful virtue signalling. Given uptake of AirNZ's carbon offsets is less than 3% of flight most kiwis act like China too.

"China has enough coal-fired power plants in the pipeline to match the entire capacity of the European Union, driving the expansion in global coal power and confounding the movement against the polluting fossil fuel, according to a report.

The nation has almost 148 gigawatts of coal-fired capacity under active construction or likely to be resumed after being suspended, Global Energy Monitor, a non-profit group that tracks coal stations, said in the report Thursday based on plant-by-plant data."

And you think that's a good thing? IMO what China (and lately the US) are doing is rubbish. Every nation should make a good effort to reduce ghg emissions. If we can do something, why should we sit back and relax and just watch everybody else do the same, while the problem is getting worse?

If I was in the CCP, I would be secretly funding climate change activists and environmental activists of all sorts. It is a great way to get your enemies fighting amongst themselves and making themselves weaker and weaker and weaker.
This is a clip from another era. It is an eye opener:

Everything is a conspiracy theory...

Bog standard Military Intellingence practise, not at all conspiracy theory. Encourage activists in your enemy's country. It is how German Military Intelligence caused Ireland and Russia to revolt in WW1.

I don't doubt subversion is a tactic. But your claim must implicate the 97% of scientists that endorse the climate change evidence as either Russian agents or lemmings (

I'm gonna need a bit more then Donald's ramblings and some old youtube video stating the obvious before I accept that claim.

If any group has fallen prey to Russian subversion tactics it would be the climate deniers that ignore the evidence and science and blindly follow Russian internet trolls spreading misinformation. Ever consider that?

97% is a fake fact

OK boomer.

Ok doomer. Given I am in the 97% it is a meaningless "fact".

This is why I shouldn't argue with climate change deniers in 2019...

China has increase emissions 58% in the past 10 years, India by over 100%. This is problematic.

How good is radiata as a nursery for native?

Hamish, it can happen but only if there is a seed source. I doubt very much whether it will happen in large forests without some human help.

I've got some 25 year old pines growing in a gully. The only thing underneath are a few tree ferns, although there would be a dense understory of chinese privet and woolly nightshade if I didn't keep at it. Whereas fenced off gullies that I weed but haven't planted are now dense with natives.

and Blackberry beats all

Not good ... radiata pine is the apex predator of forests in NZ ... it will quickly outgrow anything else with it ... it smothers gorse and broom easily .... it sucks soil moisture , shades out sunlight .. .. natives dont have a chance ... radiata is the street brawler of the environment ... can't for the life of me understand how Taxcinda & the Greens seem to love it so much...

actually Blackberry beats it, Pine has two major threats, Pitch pine canker and the pine beetle, for all we know they could already be here. Thats a risk we never take into account, Radiata Pine is extinct in California due to these two threats, and we must be at risk of environmental terrorism, being so dependant on a single cloned species.

... my pine trees killed off the blackberry easy peasy ... gorse gone ... broom beaten .... the only thing that hurt them was a 150 kph + wind about 5 years ago ...

if blackberry gets ahead of the trees when they are young it's a big problem. When you harvest those pines they will all be back.

Recently for the first time in about 12 years I drove over the Rimutaka hill road. I remember as a kid the yellow hillsides from gorse flowering. Year after year. At university pointed out in one course that the thinking was just changing about trying to control gorse, and just leave it as a nursery plant. Well my recent trip compared to the last time I'd driven over that hill I couldn't believe the transformation. Native scrub and bush all over the place. But gorse never grows tall. Pine trees though...And yes blackberry certainly is quite good at forming thick choking mats rather than gorse with enough space inbetween for other plants to start to sprout. Pinus contorta of course with a terrible reputation down south and the Kaweka range in the north island with (in hindsight) well intentioned but disastrous implementation of trying to stabilise the grazed back land using this pine species.

There is actually a way to sequester carbon and harvest wood at same time: Landfill all the trimmings from the forest at harvest time somewhere close by. Buried wood locks up carbon for the long term.
But much more sensible to just use the money that wood be wasted on carbon capture initiatives on instead building lots of PV + seasonal energy storage (pumped hydro), and innovative nuclear R&D that will be cheaper than any other large scale source of electricity withing 1-2 decades. Displacing/replacing fossil fuel consumption is a far cheaper and more effective way to reduce CO2 long term.

Meanwhile consumers, and most politicians, follow a different path. Though politicians leave the roads so crappy there is not much option. "As a result, there are now over 200 million SUVs around the world, up from about 35 million in 2010, accounting for 60% of the increase in the global car fleet since 2010. Around 40% of annual car sales today are SUVs, compared with less than 20% a decade ago.
...As a consequence, SUVs were the second-largest contributor to the increase in global CO2 emissions since 2010 after the power sector, but ahead of heavy industry (including iron & steel, cement, aluminium), as well as trucks and aviation.
...If consumers’ appetite for SUVs continues to grow at a similar pace seen in the last decade, SUVs would add nearly 2 million barrels a day in global oil demand by 2040, offsetting the savings from nearly 150 million electric cars."

In addition to making roads less safe for everyone...

NZ should develop commercial forests in Dacrycarpus dacrydioides or kahikatea. Better wood. Higher value.

you would have to treat it, already some big forestry concerns have move to Eucalypts about the country.

Gums are a tad vulnerable to airborne sparks from distant fires, tractors and the like, could be a problem.

Gums are shallow rooted... prone to be toppled by high winds ... wattles root deeply ... very hard to bowl them ... and , they fix nitrogen ..

Fix nitrogen, that's not good, horse is one of the larger contributers to lake Rotorua nutrient inflow.

Kahikatea? Soft, non-durable, lower strength.
What we really need is more long term thinking. As Keith notes, the carbon tables stop at 50years, this is not a 50 year problem, it's hundreds of years. The same goes for the time frame placed on CO2 warming effect which is only based on 100 years, completely changing the theoretical effect of sort term gases and making CO2 look way less bad.

... natives grow too slowly ... sadly ...

To slowly for what?They grew just right before we came along and stuffed things up.

It was going sweet till Helen banned rimu selective heli harvesting - and we replaced it with clear felled tropical hardwoods.

The 'we' includes early 'Polynesians' who torched the East Coast South Island forests around the 1350 mark. Stuff article quotes Lake Diamond (in from Glenorchy) where human faeces remnants were found in an ash layer in lake this thing goes back half a millennium....

Evidence of fire "abruptly and simultaneously increase[s] in sediments at about AD1345–1365 and mark[s] a period of intense or multiple fire events," the authors reported in the paper published in the journal Scientific Reports. "The peaks occur shortly after Māori arrival and during the Initial Burning Period." The researchers also found coprostanol and related substances. Coprostanol is the most abundant sterol in human feces and lasts for centuries in the right environment. "Prior to human settlement, fluxes of fecal sterols in both lakes were near zero," the authors report.

Keith, forgive me if I missed this in your explanation, but what is the impact on existing soil carbon levels when pasture is converted to forestry? Is the carbon taken up by trees merely the carbon already in the soil or do soil levels stay the same with additional atmospheric carbon being drawn into the soil & trees as the trees grow? It maybe that your calculations on area requirements for forestry are on the low side?

The carbon in wood comes from atmopheric CO2 via photosynthesis.
Some of this goes into the roots.
As to whether or not this is adding to soil carbon beyond the roots themselves gets complicated. As a general statement soil carbon comes from decaying vegetation and in mature forests should be in some sort of equilibrium.

I've seen this paper - (I can't comment on its quality):

>The effects of land use change on soil carbon stocks are of concern in the context of international policy agendas on greenhouse gas emissions mitigation. This paper reviews the literature for the influence of land use changes on soil C stocks and reports the results of a meta analysis of these data from 74 publications. The meta analysis indicates that soil C stocks decline after land use changes from pasture to plantation (−10%), native forest to plantation (−13%), native forest to crop (−42%), and pasture to crop (−59%). Soil C stocks increase after land use changes from native forest to pasture (+ 8%), crop to pasture (+ 19%), crop to plantation (+ 18%), and crop to secondary forest (+ 53%).

This paper has a veryhigh citation count ( >1700) so clearly it is something that other soil scientists read and acknowledge)

"Paired site studies in New Zealand indicate that afforestation of grassland soils will reduce upper mineral soil (mainly 0-0.10 cm layer) C levels by about 4.5 t/ha. The effect appears relatively short lived and beyond forest age 20 years there is little difference in soil C between grassland and forest. ...Short term reductions in mineral soil C arising from afforestation are likely to be offset by accumulation of C in the forest floor."

This appears to be a useful paper. I know both authors and they are of high calibre.

Yes, I worked with one of them back in the day - back when I was a runaway global warming true believer.

Spot on to focus on Permanent Forests....suggest you check article covers some similar ground in more depth

Note the sequestration potential gap between radiata and natives is far wider than you suggest over much of NZ's farmed landscapes. More often a 10 fold difference!
The MPI Look Up Tables for indigenous forest are far to generous, they are not a true average, and only in highly favorable moist and warm climatic conditions do sequestration rates match the tables.
Moisture relations are the main determinant of forest growth rates. Our indigenous forests are extremely sensitive to soil moisture levels and rainfall. Most of hill and high country farmland is in rainfall zones of below 1200mm annual rainfall. An average growth or sequestration rates for natives in these drier landscapes is a small fraction of the Look Up table projections. Our company has measured native regen in 1000mm rainfall zones in Canterbury and Marlborough where the sequestration rates are only 25-35% of the Look Up tables.
The problem with moisture loss regulation is much less of an issue for numerous introduced tree species. Radiata pine's miraculous growth and sequestration capability is first and foremost a result of its exceptional abilities to regulate water loss.

The good news is we are not just stuck with radiata. A range of temperate eucalypt species are also capable of exceptional growth and sequestration rates, and can sometimes match or outperform radiata....although eucs are usually more sensitive to soil conditions.

Eucalypt's were a major species in NZ indigenous forests until quite recently....they only died out during the ice ages about 1. 5 million years ago.

Eucs are also a far better nurse crop than pine for native understory regeneration, having less dense foliage which allows more light and moisture to reach the forest floor.

Mark Belton
Permanent Forests

Thanks Mark, Essentially we are singing in some sort of harmony. I had not seen your prior article that you refer to, so we came independently to the same general conclusions, you as an insider and me as an outsider. From your position I think you will have clearer insights than I have as to exactly what is happening currently with permanant forests, because you are closer to the action than me. Any further insights would therefore be welcome, either here or privately to my email

'An attack of pine beetle could destroy a production forest' - was recently in Canada and horrified at the vast swathes of forest being decimated by pine beetle. One theory is that a reduction in the harshness of winters that normally kill the beetle larvae was to blame. The beetle's also in colder Alaska but possibly tellingly the tree die off there was less severe. I imagine in our temperate climate an infestation would be catastrophic.

Help please, appreciate the further knowledge.

If NZ is to reach carbon neutrality, by how much does NZ's action reduce global warming by?
By 2100, how much less warm is the planet, in degrees.
For that 2100 temp reduction, what is the cost to NZ economy,

What other options were considered?

Being a mid latitude country we are actually likely to benefit from warming. Southern Hemisphere is warming less rapidly than global average due to massive moderating influence of the Ocean. Warming has minor impact on rainfall in mid latitudes compared to natural seasonal variation, and 1°C is roughly equivalent to moving 130km north or 160m down hill, increasing length and output of growing seasons - most people prefer warmer weather! 1-2mm/year sea level rise (as measured by subsidence corrected tide gauges around NZ) with no sign of acceleration in recent decades imposes relatively tiny annual mitigation costs that can mostly be dealt with by building consent rules.

Denmark - pop. similar NZ, just announced it is planning to cut CO2 emissions by 70% by 2030. They didn't bother with a cost benefit analysis.

"Temp. benefit of 0.00001°C from UN standard estimate 1000GtCO₂=0.45°C"

""Let’s ­assume that in every one of New Zealand’s elections between now and 2100, governments are chosen that continue to fulfill the promise of going to zero by 2050 and staying there. ...if New Zealand meets its promise of zero emissions in 2050 and stays at zero for five decades, then the greenhouse-gas reduction, according to the standard estimate from the United Nations’ climate panel, will deliver a temperature cut by 2100 of 0.004 degrees.
New Zealand is considering spending at least $5 trillion to ­deliver a physically unmeasurable impact by the end of the century."

Keith in answer to your question "The key emergent question is how can New Zealand put in place the incentives and institutional frameworks to plant around 45,000 hectares of permanent forests per annum on the steep erodible lands", we are currently working through a submission with a Local Council's Draft District Plan where we are starting to get support locally from a number of farmers. Essentially our submission is based around council allowing farmers to revegetate riparian margins, gullies, steep unproductive farm land with native trees, and in return council allows that farmer to either produce lifestyle block titles or if their land is high class land or if the farms are in non lifestyle areas (isolated) they have the right to transfer these titles to zoned recipient areas that are more suitable for future urban expansion.
This process would be setup so that the farmer makes a profit on the capital he spends ($35-45,000/ha including planting/weed control/fencing) and is thus incentivised to do this, in other words due to different land values association with location and land quality a farmer may need anywhere from 2-5ha of planting to produce a new title and the recipient property owners may be allowed a bonus title for every title they bought in and therefore able to subdivide down to say 5000m2 rather than 1ha.
This process we see as the best way to cater for future urban expansion as well as encourage all farmers to retire and plant out our low class land, waterways as well as enhance their existing bush areas.
We agree with your view on pines and are pretty anti eucalypt's as our experience with them is that they are more of a fire hazard and they also appear to rob the ground of all nutrients compared to pines or native.

Thanks Keith Have you thought about natural ecology rewilding at scale? See Ive yet to see a through assessment of planted/harvested pines vs planted pines vs natural ecology rewilding in terms of fossil carbon inputs, whether harvested timber locks away carbon when used for toilet paper etc. , greenhouse gas emissions, soil carbon, and biomass growth as distinct from timber growth. I agree that its all about the right tree/vegetation in the right place.

We need less humans.
It's as simple as that but politically unpalatable to talk about.
Yet our governments keep flooding NZ with more people, crazy..yes.
I do not agree with planting over productive food producing land, not one bit.
Governments worldwide will have to address overpopulation eventually.
They will kick the can down the road as long as possible because the subject is too taboo.

Forgetting how carbon is traded, surely when the pine forest is harvested much of the timber ends up in buildings and continues to sequester carbon for the buildings 50-100 year design life before the buildings are replaced and timber left to rot? Therefore pine forests would sequester additional carbon for 3 or so cycles before the timber in the initial cycle begins to rot.

I would have thought that trees suitable for use as a building material would be a natural choice in a world which is going to have to reduce the amount of concrete poured.

Is it a nuclear free moment or is it her nuclear moment.